In relation to technology regarding substrate processing apparatuses, a vertical heat treatment apparatus has been known as an apparatus in which a receiving container in which a plurality of substrates are accommodated is placed in a main body of a substrate processing apparatus. In general, in the vertical heat treatment apparatus, a plurality of substrates are transferred into the apparatus while being accommodated in the receiving container and several tens to several hundreds of substrates are simultaneously processed through a one-time process (see, for example, Japanese Unexamined Patent Application Publication No. 2009-117534).
For example, the number of wafers that can be processed by a vertical heat treatment apparatus corresponding to a 450 mm wafer is equal to the number of wafers that can be processed by a vertical heat treatment apparatus corresponding to a 300 mm wafer. However, when a wafer (substrate) has a large diameter, for example, when a 450 mm wafer is used instead of a 300 mm wafer, the sizes of members such as a receiving container or a reaction furnace should also be increased, thereby increasing the overall size of the vertical heat treatment apparatus. Thus, it takes a more time for the vertical heat treatment apparatus corresponding to the 450 mm wafer to process wafers in the same process as in the vertical heat treatment apparatus corresponding to the 300 mm wafer, thereby lowering the throughput.